Animal studies on mechanisms of oxidative stress, aging, and disease often include an experimental group receiving a certain intervention and a sedentary control group to which the experimental group is compared. The common use of a control group having no access to physical activity outside the cage poses a potential intervening variable that may affect results of studies investigating health and stress, in particular, oxidative stress. Animals participating in no physical activity outside of their cage may have different endogenous prooxidant and antioxidant levels, which over time may negatively affect their health. In previous studies where differences in biomarkers of oxidative stress or health were reported between control and experimental groups, investigators may have overestimated the effects of the intervention due to the hypokinetic effects of housing on the sedentary control animals. If animal studies are intended to generalize to other primate populations, including humans, then housing conditions and access to physical activity need to be carefully considered. The purpose of this study is to compare biomarkers of oxidative stress, a variety of health parameters, age and cause of death in animals that are grouped in three distinct ways: a) living solely in a standard cage with no access to physical activity outside the cage, 2) living in a standard cage with twice weekly one hour periods of physical activity in a large box, and 3) living in a standard cage with regular access to exercise on a running wheel. Cardiovascular parameters (blood pressure, heart rate, body weight, blood lipids) will be monitored weekly over the life span of the animals. Blood samples from a tail vein will be collected biannually and analyzed for antioxidants, lipids, and prolactin. Immediately after death, various tissues will be harvested and analyzed using a hematoxin and eosin staining method, and standard autopsy procedures performed by a veterinarian. Brain, ganglia, neurotrophic growth factor, pituitary gland, tumors, and organs and tissues will be analyzed for signs of pathology and differences among the three groups. Results of this study will distinguish cardiovascular parameters, morbidity, mortality, and biomarkers of oxidative stress due to different access to physical activity over the life span. These results will provide insight about the importance of housing and physical activity when designing animal experiments to study aging, selective health parameters, and oxidative stress.